Stephenson Amplification LJ-10 Head: LJ10 Head


Features:

  • Power scale master volume
  • Single channel pre-amp capable of smooth rich fat singing lead tones, crystal sparkling clean, and everything in between
  • Premium components for maximum reliability
  • Heavy duty custom made in Canada transformers
  • Dual primary supply transformer allowing 120v and 220v mains operation
  • Compact design, weighs just over 10 lbs
  • 15 watts class A tone from dissimilar power tube combination of 1 6V6 and 1 EL84
  • 3 12AX7 tubes in preamp
  • 4, 8, and 16 ohm speaker impedance selector
  • Ultra linear / pentode operation
  • Full featured tube buffered parallel effects loop
  • Footswitchable gain boost
  • Footswitchable effects loop bypass


Stephenson Amplification LJ-10 Operation:


LJ-10, Front Panel

Gain: Controls how clean or distorted the preamp signal is.

Treble, Mid, and Bass: EQ voiced for electric guitar

Drive: Controls the preamp level sent to power amp.

Fat: Feedback Attenuation. Controls amount of body and gain produced by the power amp.

Scale: Power Scale. Controls the amps wattage.

Basic Operation:

The Scale and Drive work together keeping the amps tone at any wattage. ‘cranked’ tone at any volume. When the Scale is set to maximum the power amp produces full wattage, any other Scale setting will produce less than full wattage. Scale set to minimum is the standby mode.

The Drive control determines the amount of saturation and compression that the power amp produces. As the amp is Scaled down the Drive should also be turned down to keep the amps natural full volume tone. A good rule of thumb is: adjust the Drive and Scale to the same settings. In other words, if the Scale is set half way then set the Drive half way. Of coarse you can adjust to taste, if a compressed saturated tone is desired, then turn down the scale and turn up the drive.


LJ-10, Rear Panel

On/Off: AC power switch

Ultra Linear/Pentode: Determines mode of operation that the power tubes are run.

4 - 8 - 16: Speaker impedance selector

Speakers: 15 watt speaker output jacks (wired in parallel)

Parallell Effects Loop:

Send: Tube buffered variable effects send. Allows the use of both, effects pedals and rack units.

Return: Variable effects return

Phase: Reverses the phase of the effects send. Some effects processors and pedals reverse the phase of the signal, this switch puts the wet (effects) signal in phase with the dry (amp) signal.

Footswitch: ¼ inch stereo jack for dual mode footswitch pedal, controls loop and a preamp gain boost.

Basic operation:

  • When powering the amp on, first turn Scale to minimum. After about one minute, slowly turn up the Scale to desired level. This is the ultimate in soft start for a tube amp. For standby mode, turn Scale to minimum.
  • Never operate without a speaker connected.
  • Set the impedance selector to match the speaker cabinet being used.
  • Ultra Linear mode of operation is a smoother warmer tone.
  • Pentode operation is the standard “guitar amp” mode of operation, and will produce a more aggressive tone.
  • Adjust effects send and return levels to create desired effect.
  • The boost button on the footswitch creates more gain in the preamp, great for solos.


LJ-10, cage removed (Front view)


LJ-10, cage removed (Rear view)

The LJ-10 uses a unique power amp design; a combination of dissimilar power tubes in a cathode-biased, class A, push/pull arrangement. The dissimilar power tubes create extra even order harmonics that produce a sound that is exceptionally full bodied for an amp rated at only 15 watts.

The dissimilar tube power amp came into being after building a custom amp for a fellow who wanted to switch between a pair of 6V6’s and a pair of EL84’s. Originally the customer wanted a pair of eight pin sockets (6V6 tube) installed and was going to use EL84 tube adaptors when he wanted to use EL84’s. I didn’t really want the tonal compromises with using the tube adaptors, so the amp was fitted with 4 power tube sockets (two 8pin and two 9pin) and a bypass (on/off) switch for each tube, so running any combination of the 4 tubes were possible. What I found was that the dissimilar combinations of tubes sounded the best, a 6V6 on one side and an EL84 on the other side. The dissimilar tube power amp tone is like taking a ‘good old’ Tweed 5E3 and blending it with a great sounding AC15, a smooth thick sound that has wonderful sparkle and clarity.

 

Contact Info :

STEPHENSON AMPLIFICATION

Mark Stephenson
PO Box 176
Parksville, BC
CANADA
V9P 2G4

Tel: 250-954-2292
Monday to Friday 10:00 AM - 6:00 PM Pacific

stephenson@telus.net